Load-carrying pallets are generally designed to be engaged by load-lifting fork blades insertable horizontally beneath the top of the pallet in multiple alternative selected directions perpendicular to each other. This arrangement advantageously maximizes the alternative directions of approach available to fork-equipped load-lifting equipment when approaching or depositing loads in restricted spaces within load storage facilities, trucks, railcars, cargo ships and the like.
With reference to FIG. 1, the most common type of pallet currently in use for many different types of loads is exemplified by the standard pallet 10 shown in FIG. 1. The pallet 10 has an upper surface 12 supported vertically by parallel spaced beams 14 extending longitudinally below the upper surface between the ends 16 and 18 of the pallet. The beams 14 create parallel, open ended, longitudinal fork-insertion spaces 20 between the beams tall enough to easily accept fork blades exemplified as 19, having either thick vertical profiles for high load-carrying capacity or thinner profiles for lower capacity, along directions of approach parallel to the longitudinal beams 14. However, for transverse directions of approach perpendicular to the beams 14, the transverse fork-insertion spaces usually include narrow slots 22 which are much more restricted in height than the longitudinal fork-insertion spaces 20, so as to insure that the transverse fork-insertion spaces do not excessively weaken the pallet beams 14. Therefore fork blades such as 21, in order to be insertable through the narrow slots 22 of the transverse fork-insertion spaces, cannot have thicknesses as great as those of the fork blades 19, and therefore cannot handle as heavy a range of loads as can the fork blades 19.
Pairs of load-weighing fork assemblies, each having a strong fork base upon which are mounted electrical load-weighing sensors for resiliently supporting the underside of a load-contacting blade member, have been coming into greater usage for the purpose of weighing palletized loads. The load weight is sensed by inserting the load-contacting blade member of each fork assembly into lifting contact with the pallet and lifting the load sufficiently to enable the weight of the load to be supported fully by the load-weighing sensors, as exemplified by U.S. Pat. No. 7,669,486 which is hereby incorporated herein by reference. However in such systems the combination of the fork base, the load-weighing sensors, the electrical conductors and the load-contacting blade member of each fork assembly, when required to support normal palletized loads weighing up to at least about 5000 pounds (2250 kg), render the resultant fork assemblies so thick that they are usually operably insertable only into the above-described taller parallel elongate fork insertion spaces 20 between the beams of the pallet, and not into the above-described transverse insertion spaces 22. This has the serious disadvantage of preventing the availability of alternative perpendicular directions of approach to the load, causing load-maneuvering problems in the many applications where maneuvering space is limited. Such problems in turn tend to discourage the use of weight-sensing fork assemblies, leading some prospective users to adopt less effective alternatives.
Accordingly what is needed is a pair of such load-weighing fork assemblies which are thin enough to avoid the foregoing fork insertion and maneuvering limitations, and yet have the strength, durability and accuracy to reliably handle and weigh the most common types of loads to be encountered.
The foregoing and other objectives, features, and advantages of the invention will be more readily understood upon consideration of the following detailed description of the invention, taken in conjunction with the accompanying drawings.